The present invention relates to a dual single reed module, particularly provided to be disposed in a wind instrument that operates in both directions of the air, such as an accordion.
The accordion is the instrument selected to give all the explanations and to provide all the information necessary to the operation, but it is to be intended that the reed according to the present invention could be mounted in all cases where a tongue must vibrate, wherein the air moves perpendicularly from above or below relative to the plane of the tongue. It is thus that in what follows of the description, we will speak of two directions of the air.
For the production of accordions, a large number of pieces is necessary.
Thus, an accordion comprises two casings connected by a bellows forming a chamber. In each of these casings, within the enclosure, there are arranged sound boards provided with openings, and mechanisms for opening and closing these openings. These sound boards generally carry several reed blocks which are supports for numerous modules also called “reed plates” in the field of the production of accordions. These modules are disposed facing the openings to be traversed or not by the air flows generated by the bellows, as a function of the actuated keys.
Each module is thus the element for the production of the sound and comprises a blade carrier. A module comprises two windows and in each one a blade fixed by one of its ends provided with a heel on said blade carrier. The blade is prolonged by its free end also called a tongue in this window.
This tongue, vibrated by the air flow passing through the window, permits producing sound.
As a function of the nature, the thickness, the dimensions of length/width and of the cutout of the tongue, there are obtained sounds corresponding to the desired notes.
In known accordions, each module comprises, for the same note, two windows and two blades for each of the two possible directions of the air. One of the blades is riveted on one of the surfaces of the module facing the first window and the other blade is riveted on the other surface facing the other window.
Each window is provided, on the surface of the module opposite that which carries the blade, with a valve, generally made of a flexible material, more particularly of leather.
Thus, for one direction of the air, the corresponding tongue is vibrated and produces the note, whilst the valve on the other window limits the escape of air through the other window.
For the other direction of the air, it is the reverse.
So as to give to this valve the desired stiffness, there is often added a resilient return element, such as a thin and narrow spring tongue.
This causes disturbance, because this arrangement with a valve is not favorable to propagation of the sound wave emitted by the vibrating tongue.
It will also be understood that for a given note, there are required a module with a blade carrier, at least two blades, two rivets, two valves, and often two resilient return elements, namely 9 pieces, which equals for even the smallest accordion a very large number of elements.
In addition to the number, it is necessary to adjust each of the contributing elements. The clearance between the tongue and the window, the curvature of the tongue to create an interstice, the resilient return element of the valve, must be made symmetrical in order to produce the same note.
It is thus known that for so-called “musette” accordions, the musicians want to have the exact note but also to have at least one note very slightly above or below it, which is to say three modules for a note with six tongues. In certain cases, there are required up to four tongues for a same note, namely eight tongues for the two directions of the air. These accordions are provided with more than a thousand tongues.
The result is the total number of pieces of several thousands for certain instruments, counting the securement means for the blade carriers and of the modules, the key mechanisms, the securement means for the reed blocks, the sound boards, in particular.
This renders long and very difficult the production and above all complicates the tuning which remains reserved for specialists who are fewer and fewer in number. The cost is very high and the delicacy increases proportionally to the complexity.
Another very great drawback is the weight that arises from the increase in the number of pieces.
The weight of an accordion, 15 kilograms for the heaviest but ordinarily 9 kilograms, prevents youngsters from carrying the instrument. They must play seated. Holding it is made difficult for all musicians and this all the more for small people.
Maintenance is complicated and the instrument is delicate because the closures for the valves in particular, of leather, are subjected to attack by mildew in the presence of moisture. The mechanical characteristics also vary greatly as a function of the temperature and premature aging takes place unless substantial maintenance is carried out by specialists who are also becoming scarce. Accessibility remains difficult. The costs are high and the delays are great.
All this leads to stagnation in the development of this instrument, even if certain countries have large production.
It would thus be useful to have modules whose tongue can vibrate in both directions of the air because the number of tongues necessary would be divided in two. Moreover, the windows and the associated pieces such as valves being omitted because they become unneeded, the weight and the size would be reduced accordingly.
Moreover, omitting valves would permit better sound propagation.
Tests have been conducted for a number of years without success.
There can be cited prior art such as French patent No. 1,350,800, in which the inventor states a goal without indicating any way to reach it.
German patent No. 34 13 382 discloses a reed that can operate in both directions, the tongue remaining in the same position and a frame being moved on opposite sides of the plane of the tongue to give a certain dissymmetry.
Such an arrangement is unsatisfactory because of the inertia of the frame and by the parasitic noises generated by such movements of large size pieces.